I plan to investigate a segment of mouse chromosome 17 situated near the major histocompatibility complex (MHC). The objectives are to elucidate the organization of genetic information; define the extent of polymorphism and/or number of loci encoding cell surface antigens in this region; determine the expression of these antigens on various populations of lymphocytes in order to identify markers of functional subsets of lymphocytes; then investigate the biochemical nature of these antigens to determine their evolutionary relationship. In order to accomplish this I will initiate experiments to search for genetic recombination in this region. These and other recombinants will be serologically analyzed by cross immunization and absorption of antisera. The biochemical characteristics will be established by immunoprecipitation of antigen and analysis by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), peptide mapping and partial N-terminal amino acid sequence analysis.